Radial flow solids separator with seal



g- 1966 F. KAISER 3,259,537

RADIAL FLOW SOLIDS SEPARATOR WITH SEAL Filed July 9, 1962 PRIOR ART INVEN T OR. FAITZ KAI-SE? AWKNEfS United States Patent C 3,269,537 RADHALFLGW SOLHDE; SEPARATUR WETH EaEAlL Fritz Kaiser, Hammel, near Augsburg,Germany, assignor to Alpine Alrtiengesellschaft Masehinenfahrik undEisengiesserei, a German company Filed .iuly 9, 1962, Ser. No. 2%,323Claims priority, application Germany, July 12, 1961, A $7,358 l Claims.(Cl. 209-444) The invention is concerned with a flow separator for theseparation of a mixture of particles into two parts according to sizerelative to a given datum and relates to separators of the type in whichthe division takes place in a rotating wheel through which the fineparticles move in a radially inward direction.

The invention deals with an important individual construction part,namely the seal of a so-called movement clearance which exists betweenthe rotating wheel and the housing of the separator. Briefly, theinvention involves the provision of an additional separation chamber,with such additional separation chamber including as one part of itsflow path for the fluid medium and the material being separated, theclearance between the rotor of the first separation chamber and itsoutlet pipe. The arrangement and dimensions of parts in the additionalseparation chamber is such that the fine particles separated out are ofsuch small size as compared to those which constitute the fines of themain separation chamber that they readily pass through the aforesaidclearance which is included in the flow path of the additionalseparation chamber.

It is among the objects of the invention to provide a simple yeteffective seal.

In the drawings the figures represent:

FIG. 1, a schematic illustration of a separator wheel according to priorart.

FIG. 2, a schematic longitudinal section through an embodiment of aseparator having the seal for the clearance according to the invention.

FIG. 3, an elevation of the separator wheel alone substantially from theright according to FIG. 2.

Separators in which the separation takes place in a wheel through whichthe fine material passes radially inwardly as a result of the inwardfiow of the flow medium, are known in many embodiments. FIGURE 1 of theaccompanying drawings shows a system common to all embodiments. Therotating wheel or separator wheel it can have on its circumference aseparating chamber 2, such chamber for example, being free of internalobstructions or, alternatively being provided with blades or louvre typemembers. The material flow 3 can be purely radial or it may have anaxial component. Any type of apparatus 4 admits the feed material to thecircumference of the rotating wheel, and the fine material or fines isdrawn off through a central discharge pipe 5.

Since the passage of the flow medium through the rotating wheel againstthe centrifugal force causes a considerable loss of pressure, there isalways the danger that a part of the material fed, while passing roundthe wheel, is sucked (arrow 6) round the front wall 7 of the separatoroutlet pipe through the necessary clearance between the rotating frontwall of the separator 7 and the stationary discharge pipe 5, and thuspollute the fines.

In order to avoid this ditficulty, it is necessary to provide a sealbetween the circumference of the rotating Patented August 30, 1966separator wheel and the stationary outlet for the fines. That is to say,a seal must be provided in the region of the movement clearance such aswill preclude passage of material therethrough. Many constructions areknown for this purpose:

It is not practical to utilize a stufiing box seal due to the high speedof operation and pollution by dust.

In order to overcome the problem, it. is not unusual to omit the frontwall 7 of the wheel and to provide a stationary wall which extendsbetween the feed organ 4 and the discharge pipe 5. Unfortunately, thisalternative, while avoiding the problem of ingress of feed materialdetracts from the effectiveness of .separation since the boundary layerof the coarse flow material creeps or slides inwardly on this stationarywall. The knowledge of this embodiment is however, important tounderstand the invention.

It is also known to mount the rotating wheel very accurately and to makethe movement clearance narrower than the finest particle the passage ofwhich is to be prevented. The disadvantage in this expedient, especiallywith very fine separating-is that a very high degree of accuracy isrequired and furthermore there is a tendency towards blocking theclearance by slipping and sticking material; such blockage leads todanger of fire.

It is further known to have two clearances behind one another and toblow therebetween clean flow medium. The movement clearance is scavengedby clean flow medium. The high expense of two clearances and thearranging for the supply of clean flow medium and the production ofpressure is disadvantageous.

It is also known to bring the flow medium, loaded with the fines, afterit leaves the opening 5, to a pressure higher than that which exists atthe circumference of the separator wheel, in an apparatus connected withthe separator wheel and then to scavenge the movement clearance withflow medium loaded with fined material towards the feed apparatus. Theproduction of pressure mentioned takes place either through the built-infan for the whole flow medium or by return blades outside the front wallof the separator wheel for a partial flow. In this case, too, theblocking of the clearance by slipping or sticking material, and aboveall, the fact that to produce the requisite pressure ventilators ofconsiderably larger diameter than the separator wheel are necessarywhich naturally cause constructional difficulties, are disadvantageous.In contrast to the teaching of the invention, the known principle isthat the return blades or ventilator blow through from the inside to theoutside of the main separation chamber through the clearance 12.

The invention, in contradistinction, lies: in the fact that (see FIG.2), at the place wherein the last-named known embodiment the returnblades provide for, from the inside to the outside, an additionalseparation chamber 111: provides for flow from the outside to the insideof the main separation chamber through the clearance 12.

The movement clearance 12. is so dimensioned that the flow mediumflowing through it flows first through the separation chamber 11adefined in part by blades 11b affixed to the outer surface of rotor wall21 and, in part, by the opposing stationary wall 14 of the housing 16.This additional separation chamber 11a which holds back all particleswhich are larger than the fines produced by the main Wheel,consequently, the principle is to interpose before the clearance 12 aspecial separation chamber so that only fines which are still finer thanthe fines of the main separation chamber can get into the clearance.

To achieve this, the amount of flow medium flowing through, andtherefore the radial components in the additional separation chamber11a, are held so small by corresponding selection of clearance 12 thatin spite of coarse separation even in a primitive additional separationchamber lla no over-size particles pass through. The requiredmeasurement of clearance 12 can be easily and empirically ascertained;it will always work out right if the Width of the additional separationchamber 11a is more than ten times the clearance width 12. By width ismeant the maximum amount by which any one of the blades 11b extendsparallel to the rotational axis and outwardly from the outer surface ofrotor wall 21.

In order to prevent too coarse particles sliding inwardly on thestationary wall 14 of the additional separation chamber 11a, one or moreledges 15 can be formed in this wall along whose outerside all materialslipping past is forced outwardly by centrifugal force. Thus, only thefiner particles can traverse the defined path and enter into thedischarge stream via the movement clearance 12.

The additional separation chamber 11a can be built onto separator wheelsof any known type.

A shape that has proved to be especially suitable is one in which theseparation chamber 11a is fitted with spiral, backwardly slanted blades1112 which, as shown in FIG- URE 3, may be mounted upon the outwardsurface 21 of the main separation rotor. The inclination of the spiralis so chosen that no material remains lying thereon (about 60 to thecircumference).

The seal according to the invention can be employed in both dry and wetseparation.

In FIG. 2, the numeral 16 indicates the housing of a wind separator inwhich the separator wheel or rotor 13 is journalled in a conventionalmanner.

Any desired type of blade, in this case unimportant, is built intoseparating chamber 17 (symbolised by the diagonal cross).

The profile of the separator wheel can also be of any desired form.Stationary members 18 are mounted in housing 16 adjacent thecircumference of the separator wheel to feed the flow medium and thematerial to be separated and also to exhaust the coarse material. Theactual type of members 18 symbolised here by a diagonal cross are againof no great importance.

The flow medium passes through the separator wheel 13 in the directionof arrow 19 from the outside to the inside and takes the fine materialwith it. A partial flow 20 of the flow medium encircling the separatorwheel 13 flows through the movement clearance 12 and mixes with the flowmedium 19 carrying the fined material so that no feed material is drawninwards from the periphery 18 of separating chamber 11.

An additional separation chamber 11a is provided outside the mainseparator wheel 13. This separation chamber 11a is bounded on one sideby the outer surface of rotor wall 21 and on the other side by thestationary inner wall 14 of the housing 16 and includes blades 11b whichmay be formed on or affixed to the outer surface of rotor wall 21.

In order that no coarse particles can slide into the boundary layer fromthis wall 14, the said wall is provided with two ledges 15. Coarseparticles which arrive therein are taken by centrifugal force from theouter side of these ledges 15 outwardly into the area of the blades 11and passed outwardly.

The radial component of the side flow 21 is so small due ot the chokingby the narrow clearance 12 that the margin of division in the separationchamber 11a is so low that, in spite of coarse separation, no particlesmove inwardly which are so large that they would affect the mainseparation of separator 17.

As sharp separation by the separation chamber 11a is not required theshape of blades 11b is not of importance and those whose configurationis as shown in FIG. 3 have proved satisfactory.

What is claimed is:

1. In a separator for finely-divided solid materials, a first fluid flowseparation chamber comprising a separation rotor rotating within .astationary housing, inlet means for admitting the material to beseparated and the fluid medium to the periphery of said separationrotor, a stationary outlet pipe communicating with said separationchamber substantially at the axis of said rotor and defining apredetermined circumferential clearance therebetween, and an additionalseparation chamber including a second rotor and defined at least in partby said separa tion rotor and said stationary housing, said additionalchamber communicating substantially at the periphery of said rotor withsaid inlet means and communicating with said outlet pipe substantiallyonly through said clearance between said outlet pipe and thefirst-mentioned rotor to thereby define a flow path for said fluidmedium from said inlet means through said additional separation chamberand said clearance into said outlet pipe, said second rotor includingblades which are so disposed on said rotor relative to its direction ofrotation to permit only particles of said materials which are finer thana predetermined size to travel along said fiow path with said fluidmedium, said additional separation chamber including means for sorestricting the flow of said fluid medium therethrough that thoseparticles traveling under the influence of said fluid medium to thecenter of said second rotor and through said clearance into said outletpipe are smaller than the particles which pass into said outlet pipefrom said first separation chamber.

2. The separator as defined in claim 1 wherein said first separationchamber includes a disc-like rotating end wall forming a part of saidrotor in said first separation chamber and said additional separationchamber is defined at least in part by said end Wall and also by aninner wall of said stationary housing, said second rotor comprisingspiral blades on said end wall.

3. The separator as defined in claim 1 wherein said first separationchamber includes a disc-like rotating end wall forming a part of saidrotor in said first separation chamber and said additional separationchamber is defined at least in part by said end wall and also by aninner wall of said stationary housing, said inner wall of saidstationary housing defining a plurality of ledge-shaped portions eachbeing substantially parallel to the axis of rotation of said rotor andwith the remaining inner surface of said stationary housing which inpart defines said second separation chamber being inclined inwardlytoward the plane of rotation of said second rotor with increasing radialdistance from the axis of said second rotor.

4. Apparatus for use with a fluid flow separator for finely-dividedsolid materials of the type having in combination, a first rotorrevolving in a stationary housing and including a means for admittingboth the material to be defined and the fluid medium into said housingadjacent the periphery of said first rotor and also an outlet pipe whichcommunicates with the axis of said first rotor but with a predeterminedclearance between said pipe and said first rotor, said predeterminedclearance being selected to be sufliciently small so that the finesseparated out in said first rotor cannot pass therethrough and insteadsubstantially all enter said outlet pipe, the improvement whichcomprises a sealing means to prevent said material from being drawnthrough said clearance from outside said housing and thereby cloggingsaid clearance, said sealing means including in combination a secondseparation chamber defined in part by said housing and in part by rotormeans, said second separation chamber communicating substantially at theperiphery of said second rotor with said inlet means, said secondseparation chamber communicating with said outlet pipe through saidclearance to thereby define a flow path for said fluid medium from saidinlet means through said additional separation chamber and saidclearance into said outlet pipe, said rotor means including blades whichare so disposed relative to the direction of rotation of said rotormeans to permit only particles which are smaller than a predeterminedsize to travel along said flow path with said fluid medium, and meansfor restricting the flow of fluid mediumth'rough said second separationchamber, said last-named means in combina- 10 tion with said secondrotor being jointly operable to separate out particles in said secondseparation chamber which are smaller than those separated out in saidfirst separation chamber, whereby said smaller particles readily passthrough said clearance and into said outlet pipe.

References Cited by the Examiner UNITED STATES PATENTS 2,207,317 9/1940Gear 103115 2,361,758 10/1944 De Fligue 209144 3,089,595 5/1963 Kaiser209-144 FRANK W. LUTTER, Primary Examiner.

1. IN A SEPARATOR FOR FINELY-DIVIDED SOLID MATERIAL, A FIRST FLUID FLOWSEPARATION CHAMBER COMPRISING A SEPARATION ROTOR ROTATING WITHIN ASTATIONARY HOUSING, INLET MEANS FOR ADMITTING THE MATERIAL TO BESEPARATED AND THE FLUID MEDIUM TO THE PERIPHERY OF SAID SEPARATED ANDTHE A STATIONARY OUTLET PIPE COMMUNICATING WITH SAID SEPARATION CHAMBERSUBSTANTIALLY AT THE AXIS OF SAID ROTOR AND DEFINING A PREDETERMINEDCIRCUMFERENTIAL CLEARENCE THEREBETWEEN, AND AN ADDITIONAL SEPARATIONCHAMBER INCLUDING A SECOND ROTOR AND DEFINED AT LEAST IN PART BY SAIDSEPARATION ROTOR AND SAID STATIONARY HOUSING, SAID ADDITIONAL CHAMBERCOMMUNICATING SUBSTANTIALLY AT THE PERIPHERY OF SAID ROTOR WITH SAIDSTATIONARY HOUSING, SAID ADDITIONAL SAID OUTLET PIPE SUBSTANTIALLY ONLYTHROUGH SAID CLEARENCE BETWEEN SAID OUTLET PIPE AND THE FIRST-MENTIONEDROTOR TO THEREBY DEFINE A FLOW PATH FOR SAID FLUID MEDIUM FROM SAIDINLET MEANS THROUGH SAID ADDITIONAL SEPARATION CHAMBER AND SAIDCLEARENCE INTO SAID OUTLET PIPE, SAID SECOND ROTOR INCLUDING BLADESWHICH ARE SO DISPOSED ON SAID ROTOR RELATIVE TO ITS DIRECTION OFROTATION TO PERMIT ONLY PARTICLES OF SAID MATERIALS WHICH ARE FINER THANA PREDETERMINED SIZE TO TRAVEL ALONG SAID FLOW PATH WITH SAID FLUIDMEDIUM, SAID ADDITIONAL SEPARATION CHAMBER INCLUDING MEANS FOR SORESTRICTING THE FLOW OF SAID FLUID MEDIUM THERETHROUGH THAT THOSEPARTICLES TRAVELING UNDER THE INFLUENCE OF SAID FLUID MEDIUM TO THECENTER OF SAID SECOND ROTOR AND THROUGH SAID CLEARENCE INTO SAID OUTLETPIPE ARE SMALLER THAN THE PARTICLES WHICH PASS INTO SAID OUTLET PIPEFROM SAID FIRST SEPARATION CHAMBER.